There's been a lot of positive news to come out of Barcelona over the international break. Aside from the injury scare Sergio Busquets has faced, the club has had nothing but very, very good news - including the great Lionel Messi joining the squad in full training with less than a week to go until El Clasico. That's an incredibly positive thing for the club, as it provides the best threat in the world in the biggest match the club is guaranteed to play in.
There needs to be some consideration, though, that Messi may not be capable of starting in such a big match. After having missed two months of play, going from 0 to 100 is going to be a very dangerous task for the Argentine. Aside from a potential relapse from rejoining the game so quickly, the biggest risk is that Messi simply won't be ready. Any given match requires incredible endurance - endurance that can only truly be garnered by consistent play. Unfortunately, that's something Messi hasn't experienced.
Given the chances that Messi may need to start the match on the bench, and be a late-match dynamic threat, I believe it's necessary to approach tactical innovations that will truly give Barcelona the best opportunity to shut down Real Madrid. As much fun as the 4-3-3 has been, it will largely be ineffective with a player such as Munir or Sandro manning the right wing, and their inclusion in the squad truly just means a better player must be left out. If that's the case, I believe that it's necessary to revisit the idea of formations, as a whole, in the journey of finding the best tactical option for the squad.
With Neymar and Suarez in the squad, and no quality third attacking option, a two forward system seems to be ideal. From the start, the club can look for variations of a 3-5-2, a 4-4-2, or a 5-3-2. Given the attacking nature of the players, we can immediately knock the 5-3-2 out of the discussion, as well - which gives a pretty small list of formations that can (and should) be discussed.
When discussing tactical formations, it's necessary to find their inherent advantages and disadvantages - and how the club is capable of exploiting them. The first formation to discuss would be a standard 3-5-2 - with two pivots, two wing backs, and an attacking midfielder. The main advantage here is the density in defense - which is why the formation is widely regarded as the formation of underdogs. In defense, the wing backs fall back and form something of a five-man back-line. The central defenders are able to smother any attacks in or near the box while the wide players are capable of shutting down the wings.
The biggest disadvantage here is the lack of width in attack - which shouldn't be a surprise. If the wing-backs are busy playing in the defense, they'll struggle to provide any sort of quality width in the attack. They'll never fully be able to push into the attack, as the wings would immediately become a threat for the counter. Given the lack of wide players anywhere else on the pitch, the formation immediately becomes limited horizontally, which limits the amount of space the attack can operate in.
Obviously there's a major advantage in the fact that it pits Busquets in a position to be defensive while pitting Iniesta in a position to control the midfield and returns Rakitic to his natural position as an attacking midfielder. The formation also allows Barcelona to take advantage of the fact that they have five very quality central defenders. The disadvantage is that it requires Dani Alves to operate at both ends of the pitch more frequently - something with which he already struggles. I believe Alba would be fine in this role - as it exploits his stamina and pace - but the other side of the attack (and defense would struggle). Given that most of Madrid's attacks will come from our right flank, it's not ideal to use a formation that limits the effectiveness on that side.
That brings me to the 4-4-2. This is also a very defensive formation in nature, though it doesn't force the squad into a defensive game. There are a few variations I could see the club using with this formation.
The first would be the most likely, with a back-line that reads Alba - Mascherano - Pique - Alves from left to right, and a midfield that reads Iniesta - Busquets - Rakitic - Roberto, similarly. The natural wing-backs in the formation allow both Roberto and Iniesta to take more central roles while also providing two players comfortable playing wide when necessary. As I mentioned above, this formation provides more defensive solidarity - with two solid lines making it tough for the opposition to penetrate. It does make it more difficult for the offense to consistently function, and it puts two players (Alba and Alves) that aren't defensive by nature in very defensive positions.
One adjustment that could be made is simply removing both wingback and operating with four astute defensive players - using a backline that reads Mathieu - Mascherano - Pique - Bartra, from left to right, and replacing two naturally central midfielders with Alves and Alba. Realistically, if this were to happen Rakitic and Roberto would lose their spot, with a midfield reading Alba - Iniesta - Busquets - Alves. That really puts both Alves and Alba in a great position, as it allows them freedom in attack with great coverage in the back-line. The biggest disadvantage is that it creates a disconnect within the squad. The fullbacks essentially become useless in attack, and limits the options to just six of the 11 players.
The easy adjustment, from there, is to combine the two options - pushing one wing-back forward into a wide midfield role and replace him with a more defensive player. This could either be accomplished by using Mathieu on the left-wing in a very defensive role and pushing Alba as a left midfielder - subsequently moving the other midfielders right, and Roberto out of the starting XI - with Alves operating as a wing-back, or vice-versa. Alves could operate as a wide midfielder (a role he's largely held when Barcelona hold possession in Lucho's 4-3-3), with Alba operating as a wing-back, and Bartra replacing Alves on the side.
Regardless of how you adjust it, this is a way for Barcelona to take advantage of their defensive numbers while putting players in a more comfortable position of operation. From here, it's more of a question of which style of the third variation is best for the club - Alba or Alves operating as the wingback.
To me, the question largely comes down to which flank is the more important to constantly have covered. Given that one of the flanks will have a defensive fullback constantly, that side can stay stuck in - constantly ready to cut out an attacks down the side - it's necessary to decide which side needs to be most astute defensively. For me, it's more important that that side be our right side - the one with Cristiano and Marcelo. Given that, I would operate Alves as the wide-midfielder and allow Bartra to cover the right side the way he did against PSG.
From there, Alba would act as a wing-back - allowing Iniesta to take up a more central role in the attack and a wider role in defense. It would allow Busquets to cover the central defenders, Iniesta to roam the midfield for space to control the match, and Rakitic to continue his box-to-box style that he's thrived in since joining the Catalan club.
As you can see, it largely ends up acting as a 4-3-3 in attack, with Alves operating in half-space, and the midfield trio returning to normal. Alba would operate normally, as well. The only difference between the normal 4-3-3 and the new formation in attack is the RB. Instead of Alves operating like a wingback, and using an inverted winger on the right side, Bartra would be a defensive fullback and Alves would operate as more of a true winger/wide midfielder.
In defense, the team drops back into a standard 4-4-2. The right side of the defense has very little to do, given Bartra's lack of necessary movement, which would allow for coverage on the left side until Iniesta and Alba moved back into position.
While it's unlikely that Enrique will vary from the 4-3-3 he's so fond of using, it seems as though this formation is one of the best options available. It allows for every player on the pitch to play a natural style while limiting weaknesses, exploiting strengths, and leaving depth within the squad on all fronts.